Vehicle destination sign mechanism



March 6, 1956 H. Y. MAGEOCH 4 2,736,973

VEHICLE DESTINATION SIGN MECHANISM Filed Feb. 26, 1952 2 Sheets-Sheet 1 INVENTOR HARRY Y I LEI MHGEOC H ATTORNEY March 6, 1956 H. Y. MAGEOCH VEHICLE DESTINATION SIGN MECHANISM Filed Feb. 26, 1952 2 Sheets-Sheet 2 M as I} v5 3 l "fl 38 I I /,Y I53 4% 1/ ATTORNEY INVENTOR HARRY YHLE MAGEO H United States Patent VEHICLE DESTINATION SIGN MECHANISM Harry Yale Mageoch, Havertown, Pa., assignor to Electric Service Manufacturing Co., Philadelphia, Pa., a corporation of Pennsylvania Application February 26, 1952, Serial No. 273,391

4 Claims. (Cl.'40'-93) This invention relates generally to vehicledestination sign mechanisms and is more particularly concerned with an improved construction thereof atfording certain functional advantages.

A vehicle destination sign mechanism, e. g., the type commonly used on buses, generally comprises a pair of vertically spaced parallel rollers mounting respectively the opposite end portions of a curtain which bears a series of destination signs on the outer face thereof so that the sign on the portion of. the curtain intermediate the rollers is disposed in plain view of a person looking at the mechanism from outside the bus. Known constructions of these mechanisms have not proved to be entirely satisfactory because when means is provided for drawing the curtain taut such means commonly acts to cause creeping of the curtain so that after a time the sign intended to be displayed is dislodged from its proper place.

Accordingly, it is an object of the present invention to provide a vehicle destination sign mechanism of the type having a spring-loaded roller for keeping the curtain taut with means for preventing the sign intended to be displayed from becoming dislodged from its proper place due to the action of the spring loaded roller.

Another object of the present invention is to incorporate in the parts operatively connecting the idler and spring-loaded rollers of such a vehicle destination sign mechainsm means for locking said mechanism against such movement thereof due to the action of the springloaded roller as would dislodge from its proper place the sign intended to be displayed.

Still another object of the present invention is to in corporate in the parts operatively connecting the idler and spring-loaded rollersxof such a vehicle destination sign mechanism means operating on. a single element and acting to lock said mechanism against such movement thereof due to the action of the spring loaded roller as would dislodge from its proper placethe sign intended to be displayed.

And still another object of the present invention is to provide an improved clutch arrangement for a pair of revoluble members which affords free movement of said members when one of them is the driver, and which prevents free movement of said'memberswhen the other of said members is the driver.

Other objects and advantages of the present invention will appear more fully hereinafter, it being understood that the present invention consists in the combination, construction, location and relative arrangement of parts, all as will be more fully described hereinafter, as is shown in the accompanying drawings and will be pointed out in the appended claims.

In the accompanying drawings:

Figure 1 is a rear view of a vehicle destination sign mechanism embodying thepresent invention, parts being omitted or broken away to better expose others.

Figure 2 is a sectional elevation on. linel2.2.of.Figure 1, the curtain being omitted.

2,736,973 Patented vMar. 6, 1956 Figure 3 is a front elevation showing the structure of Figure 2, the curtain being omitted.

Figure 4 is an enlarged sectional elevation substantially on line 4-4 of Figure 2, parts being omitted for the sake of clarity.

Figure 5 is a reduced sectional elevation on line 55 of Figure 4, parts being omitted for the sake of clarity.

Figure 6 is a diagrammatic view showing the clutch means locked against rotation of its associated parts by a dominant force exerted by the driven member, as indicated by the full line arrow, the driving member being shown as acting in the opposite direction with a lesser force, as indicated by the broken line arrow.

Figure 7 is similar to Figure 6 but shows the clutch means released for rotation of its associated parts by a dominant force exerted by the driving member, as indicated by the broken line arrow, the force exerted by the driven member being in the direction indicated by the full line arrow.

Figure 8 is a perspective view showing the disassembled parts of the clutch means.

Figure 9 is a section on line 9S of Figure l; and

Figure 10 is similar to Figure 9 but shows the bearing blocks separated for receipt (or discharge) of the associated roller shaft member disposed therebetween.

Referring now more particularly to the drawings, it will be observed that the frame of the vehicle destination sign mechanism comprises a pair of side members 11 and 12 and a rear member or back plate 13 suitably rigidly secured together and, in plan section, forming a U-shaped supporting structure, the bight thereof presenting forwardly. Members ill and 12 are preferably rightangularly bent plates which are respectively provided with inturned flanges which underlie and are secured to the opposite ends of the back plate 13 and with freely extending side portions 14 and 16 which form the opposite side walls of the mechanism supporting frame.

Disposed between the opposite side walls 14 and 16 of the supporting frame are a pair of curtain roller units 17 and 18 arranged in vertically spaced parallel relation to one another and positioned in a vertical plane spaced frontally of the rear plate member 13. Mounted upon the roller units 17 and 18 is a curtain having suitably printed thereon a series of station designations, the opposite ends of the curtain being suitably secured to the rollers so that as it is wound upon one and unwound from the other of said rollers an intermediate portion of the curtain extends between the roller units and presents to view one or another of the station designations printed thereon.

The lower roller unit 17, which serves as the idler roll for the curtain, essentially comprises a main tubular member 20 fitted at its opposite ends with flanges 21 and Y22 having suitably fixed therein oppositely extending end supporting shafts 23 and 24.

The upper roller unit 18 also comprises a main tubular member 25 fitted at its opposite ends with flanges 26 and 27 having suitably mounted therein oppositely extending end supporting shafts 23 and 29. The tubular member 25 of the upper roller unit is, however, conventionally spring-loaded by means or" an internal coiled spring (not shown) so as to impart to the member 25 a bias which tends normally to rotate it relatively to its end shaft 28 and to this end the shaft 2% is revolubly 1 journalled in the flange 26.

Suitably keyed to the end shaft 23 of the lower roller unit 17 for rotation therewith is a spur gear 33, while keyed to the end shaft 28 of the upper roller unit is a spur gear 32, it being. noted that the latter gear. and its associatedtubular member 25 are relatively revoluble.

The spur-gear;31 and 32 are disposed in coplanar relation immediately to the inside of the side wall 14 of the supporting frame.

The extreme outer end portions of the supporting shafts 23 and 28 are each rotatably jourualled within short bushings 33 suitably rigidly secured in openings formed in the side wall 14 of the supporting frame, while the extreme outer end portions of the opposite shafts 24 and 2? are each rotatably journalled within a bearing unit 34-. Each of the latter comprises a fixed bearing block 36, a relatively movable bearing block 37 spring-pressed towards the fixed block by means of a spring 38, and a retaining member 39. The retaining member 39 is preferably in the form of a sheet-metal housing of box-like form having a top wall 46, parallel side walls 41-42 and parallel end walls 43-44 The end walls are respectively flanged, as at 46 and 47, while the side wall 41 is provided with an opening 48 which extends across the major part of the top wall 40. The flanges 46 and 47 have openings formed therein by means of which they are suitably ri idly secured to the inside face of the side wall 16 of the supporting frame structure, the retaining member 3-9 being thereby disposed with its top wall as in spaced relation to the aforementioned side wall 16 of the frame and with the opening 48 presenting forwardly of said frame.

The fixed bearing block 36 is seated within the retaining member 39 against the end wall 44 thereof, said block being of a size to fit more or less snugly between the top wall 4d of the retaining member 39 and the side wall 16 of the mechanism frame and between the side walls ll iz of the retaining member. The movable bearing block 37 is disposed in vertically aligned relation with respect to the fixed block 36 and is similarly seated within the retaining member 39 but against the end wall 43 thereof, said movable bearing block 37 being normally urged toward the fixed block 36 by a coil spring 38 disposed to react between the end wall 43 of the retaining member and the proximate face of the movable block 37. To prevent displacement of the coil spring 38 the aforementioned proximate face of the movable block 37 is provided with a depression 51 for receiving the associated end of the coil spring 33. In addition, the end wall 43 of the retaining member is provided with an inwardly pressed element 52 which engages within the v opposite end of the coil spring 33.

Opposed frontal portions of the proximate faces of the bearing blocks are relatively tapered to conjointly form a flared passage 53 for entrance of the roller shaft 24 (or 29) into journalled position between the meeting faces of the bearing blocks 36 and 37 of their retaining member 39, said meeting faces being complementally notched to form a seat 54 within which the roller shaft is revoluble. It will be noted that the flared entrance 53 of each bearing assembly 34 is in registry with the opening 4-8 in the frontal side wall 41' of the retaining member 39 for the assembly, and that the bearing assemblies 34--34 for the shafts 24 and 2.9 are each mounted with the stationary bearing block 36 thereof in position to restrain movement of the shafts 24 and 29 toward each other, thereby assuring a fixed minimum spacing between the roller units 17 and iii.

The clutch means of the present invention essentially comprises a fixed element 56 and a coacting member 57, the latter being expandible on said element 56 to permit elative rotation therebetween and contractible on said element to prevent such relative rotation. The fixed element 56 is in the form of an elongated stud made of tubular stock having a large diameter central bore through the major portion of its length and a small diameter central bore through the remainder of its length. The stud 56 is rigidly secured to the side wall 14 of the supporting frame for the mechanism by a screw 58 projected through said side wall and the small diameter bore in the end of the stud 56 for threaded engagement with a spindle 59, the latter being provided with an enlarged diameter portion disposed in the large diameter bore of stud 56 with its inner end abutting the shoulder formed in the tubular stud by the aforementioned large and small diameter bores thereof. It will be seen that the stud S6 is thus disposed with its small diameter bore end in abutting engagement with the inner face of the supporting frame side wall 14 and with its large diameter bore end extending inwardly therefrom. For securing the stud 56 against rotation about its central axis the side wall 14 of the frame structure is provided with an inwardly projecting lug 61 which seats Within a recess 62 suitably formed in the outer end of the stud 56, the interfitting lug 6i and recess 62 being eccentric to the axis of the stud 56.

The aforementioned coacting member 57 is in the form of a relatively stiff coil spring embracing an intermediate portion of stud 56, the inside diameter of the coil spring being normally slightly smaller than the outside diameter of the stud 56. The opposite end portions 63 and 64 of the coil spring 57 extend radially outwardly from the main body portion thereof and are circumferentially spaced apart approximately 60 degrees of the coil circumference.

The manually operable mechanism for rotating rollers 17 and 13 through the intervention of the clutch means of the present invention includes a knob 66 operatively connected to the rollers through a gear train associated with said clutch means. For mounting the knob 66 the spindle 59 is provided with a reduced inner end portion 67 threaded into one side of a bearing element 68 having a central bore 69, the axis of the latter being disposed at right angles to the axis of spindle 59. Fixedly secured between that side of the bearing element 68 which is engaged by' the threaded end 67 of the spindle and a shoulder 70 suitably formed on the latter is a flat, circular spacer disk or flange element 71. The forward end portion of a shaft 72 is journalled in the bore 6% of the bearing element 68 and is horizontally disposed thereby, the rear end portion of said shaft 72 being projected through the inwardly turned flange of the frameforming side member 11 and its overlying rear member or back plate 13. The operating knob 66, which is keyed to the freely projecting outer end of the shaft 72, is provided with a shaft-engaging hub 73 disposed in abutting relation to the rear face of plate 13 to limit inward movement of the operating shaft 72, while movement of said shaft in the opposite direction, i. e., outwardly of the plate 13, is prevented by means of a collar '74 releasably locked to the shaft, as by a set screw 75. Thus, the operating shaft 72 is restricted against axial movement but is free to be-rotated in either direction by its operating knob 66, which latter could be replaced by any form of handle convenient for rotating the shaft 72.

The gear train hereinabove referred to includes a set of beveled gears actuated by turning of the knob 66, the beveled gears in turn actuating a set of spur gears including the spur gears 31 and 32. A pair of spur gears 76-76 are arranged respectively in mesh with the spur gears 31 and 32, each of the former being suitably rotatably secured to the frame side wall 14, while a single spur gear 77 is arranged in mesh with both spur gears 76--76. The intermediate spur gear 77 is formed with an axially offset web 78, axially opposed hubs 79 and 81 of respectively large and small outside diameters, and a central bore 82 extending commonly through said hubs. The spur gear 77 is supported upon a pair of ring members 83-453 carried by the stud 56 and disposed respectively at opposite ends of the coiled spring 57 on the stud, the rings 8383 having a rather loose fit on stud 56, and the bore 82 affording a loose fit of the spur gear 77 on the rings 83-83. The outer end of the large hub 79 is disposed in abutting relation to the inner face of frame side wall 14, a felt washer 75 being mounted thereon, while the small diameter hub 81 extends axially inward of said side wall. i

The gear 77 is provided with akey-stone-shaped internal notch 84 extending axially therethrough, said notch" 84 being defined by the curved top edge 86 disposed intermediate the, outer surfaces of the hubs 79.and 81 and by radially extending side edges 87 and 88 spaced approximately 60 degrees apart, said side edges extending inwardly from the curved top .edge86 of the notch 84 so that the reduced end thereof opens into the central bore 82 of the gear '77. The inwardly projecting small diameter hub 81 of said gear is longitudinally slotted, as at-84 in continuation of the notch 84, as is most clearly shown in Figure 8. It will be noted that the notch 84 and its slotted extension open into the central bore 82 of gear 77 in order to dispose the outwardly extending end portions 63 and 64 of coil spring 57 between the side edges 87 and 88 of said notch and slot.

The aforementioned set of beveled gears includes a beveled gear 89 having an axially offset web 91 and a pair of axially spaced hubs 92 and 93 of respectively large and small diameters. A large diameter central bore 94 extends through the large hub 92 and communicates with a small diameter central bore 96 extending through the small hub- 93. The beveled gear 89 is supportedupon the spur gear 77, the large bore 94 of the gear 89 being of such a diameter as to telescopically receive the small hub 81 of the spur gear 77 for relative rotation of said gears, the small bore 96 of the gear 89 being in turn of such a diameter as to loosely receive the spindle 59. Thebevel gear 89 is thus disposed with the inner face 97 of its web 91 abutting the free end of the small hub 81 of the spur gear 77, and with its large diameter hub 92 interiorly of the toothedpart of the spur gear 77. A flat washer 95 is preferably interposed between the bevel gear 89. and the flange element 71.

Formed as an integral part of the large hub 92 of the bevel gear 89 is a lug 98 projecting radially into the bore 94 and extending axially the full depth thereof and beyondto overhang the hub 92 (see Figure 8). In cross section, the overhanging portion of element 98 is generally of inverted trapezoidal shape having radially spaced inner and outer surfaces 99 and 101 and radially extending opposite side surfaces 102 and 103, the latter being spaced apart approximately 30 degrees of the circle of the hub 94. Thus, the lug. 98 is of a width approximately equal to half that of the correspondingly shaped notch 84 formed in the web of the spur gear 77, said lug being further of such depth as to present its arcuate inner surface 99 in coincidence with the cylindrical inner surface of the slotted hub 81 of said spur gear 77. Thus, when the bevel gear 89 is supported on spur gear 77 as described hereinabove, the lug'98 projects into the slot 84 of the hub 81 of the spur gear 77 and. between the circumferentially spaced, radially projecting ends 63 and 64 of the coil spring 57 which is carried by the stud 56 and' together with the latter is fitted with the slotted hub 81 of the spur gear 77.

For actuating the bevel gear 89 a second bevel. gear 104 is suitably fixed, as by a set screw 105, on shaft 72 for rotation therewith and is disposed thereby between the collar 74 and the bearing element 68 in meshed engagement with said bevel gear 89.

For proper operation of the mechanism, the coil spring on the stud 56 is of such fit that when the bevel gear 89 is rotated to cause its internal lug 98 to engage one or the other of the radially extending ends 63-64 of the coil spring, the latter is expanded to permit 'it to rotate freely relatively to its supporting stud 56,-while, when the spur gearv77 is rotated to cause either side edge of the slot 84 to engage the proximate radially extending end of the coil spring 57, the latter is contracted into binding or clutching engagement with the stud 56 to. prevent rotation of the coil spring.

For moving the curtain down or up, the knob 66 may be-turned. respectively clockwise or counterclockwise as viewed in Figure 1. Of course, the shaft 72 and its as- -sooiated bevel gear 104 are actuated-accordingly, the

' latter'actingin turn to rotate the gear 89. The lug 98 turns with the gear 89, and initial movement thereof brings one of its sides 102 or 103 into engagement respectively with oneor theother of the radially extending ends 63-64 of the coil spring 57. Additional turning movement effects expansion of the coil spring 57 with resulting rotation of the latter about the stud 56 until the engaged end 63 (or 64) of the coil spring is shifted into engagement with the proximate edge of the slot 84 formed :in the hub 81 of the spur gear 77. Still further turning movement of the lug 98 then causes the spur gear 77 to rotate with the coil spring 57 and the bevel gear 89. As an example, when the knob 66 is turned clockwise, as viewed in Figure 1, bevel gear 89 and its lug 98 also turn clockwise as viewed in Figures 2 and 5, the initial clockwise movement of the lug 98 presenting its side edge 103 in engagement with the radially extending end 64 of the coil spring 57. Thereafter, continued clockwise turning movement effects expansion of the coil spring 57 and rotation thereof together with the lug 98 about the stud 56 until the radially extending end 64 of the coil spring contacts the edge 88 of notch 84 formed in the spur ,gear 77. Still further clockwise turning movement of the lug 98 causes the spur gear 77 to turn with coil spring 57 and bevel gear 89 about the stud 56. It will be noted that rotation of bevel gear 89 and its lug 98 either clockwise or counterclockwise is relative to spur gear '77 until one or the other of the radially extending ends 63 or 64 of the coil spring is pressed by the lug 98 into engagement with the proximate side edge 87 or 88 of the slot 84 formed in the spur gear 77. Thereafter, the bevel gear 89 and the spur gear 77 rotate together to drive the spur gears 31 and 32 in the same direction through the intervention of spur gears 7676, as will be evident.

The roller units 17 and 18 are provided respectively with means (not shown) for anchoringthe opposite end portions of the curtain 19 thereof. With the mechanism in its condition as shown in Figure 2 and with the curtain 19 thus anchored and wound about the curtain tubes 20 and 25, it will be evident that by virtue of the spring. loaded condition of the curtain tube 25 it will tend to maintain constantly taut that portion of the curtain which extends between the rollers units 17 and 18. The spur gear 32 immediately associated with the spring loaded curtain tube 25 tends, under the influence of the curtain spring (not shown), to rotate in direction opposite tothat of the curtain tube 25, that is in clockwise direction. The spur gear 32 thus tends to rotate the spur gear 76 in mesh therewith in counterclockwise direction and the last mentioned spur gear in turn tends to rotate the central spur gear 77 in clockwise direction. Through the intervention of the second spur gear associated with the roller unit 17 and in mesh with the spur gear 31 thereof, the latter is adapted to be driven in the same direction as the central spur gear 77, that is clockwise, from which it will appear that as the spur gear 77 is rotated in clockwise direction upon operation of the knob 66 to unwind the curtain from the upper spring loaded roller unit 18, the spur gear 31 is simultaneously rotated to Wind the bottom end of the curtain upon the lower roller unit 17. Of course, the central spur gear 77 may be rotated in either clockwise or counterclockwise direction to shift the extended portion of the curtain either downwardly or upwardly between the roller units 18 and 17 as may be required, such rotation of the spur gear 77 by operation of the knob 66 being effected through engagement of the lug 98 with one or the other of the radially extending ends of the coil spring to free the same for rotation about the fixed supporting stud 56.

However, rotation of the spur gear 77 in either direction by rotation of one or the other of the curtain roller units as the prime mover is precluded the instant that either side edge of the notch 84 formed in the spur gear 77 engages the proximate radially extending end of gra ers the coil spring 57 to contract the latter and so clutch it to the stud 56. It will thus be evident that means has been provided for absorbing the reactive force enduced by the action of the internal spring means (not shown) of the spring loaded curtain tube 25 and transmitted to the fixed stud 56 through the spur gear 32, the spur gear 76, the spur gear 77 and the coil spring 57, in the order named.

For maintaining the curtain 19 taut regardless of its position on the roller units 17 and 18, it is initally drawn taut under the biasing influence of the roller tube 25 when as much of its as possible is wound on said tube. Thereafter, the knob 66 may be turned clockwise, and the parts operatively connecting it with the spur gears 31 and 32 will turn these spur gears clockwise at the same rate. However, until the curtain 19 is equally distributed between the roller units 17 and 18 the biasing influence of the latter increases beyond the initial setting due to relative movement of the curtain tube 25 and the spur gear 32, after which the biasing influence of the roller unit 18 will decrease to the initial setting. It will be apparent, therefore, that the biasing influence of the roller unit 155 will always be maintained regardless of the position of curtain 19 on the roller units 17 and 18, and as a consequence the spur gear '77 is normally urged to rotate clockwise so that the side elge 37 of notch 84 of the central spur gear '77 is constantly urged against the radially extending end portion 63 for contracting coil spring 57 into clutching engagement with the stud 56, as see Figures 6 and 7. In order to move the curtain w down or up between roller units 17 and 18, the knob 66 is turned in the apppropriate direction with suiiicient effort to cause the lug 98 to move against one of the radially extending ends 63 and 64- of the coil spring 57 whereby to not only overcome the aforementioned force tending to constantly contract coil spring 57, but also to cause the coil spring 57 to expand so that it may be turned freely about the stud 56, as see Figure 7.

From the foregoing, it will be apparent that the spur gear 77 with its internal notch 84 and slotted hub 81 serves, under the influence of the spring-loaded roller unit 18, as the actuator to clutch the coil spring 57 firmly upon its fixed stud 56 to thereby prevent movement of any of the entrained gears, while the bevel gear 92 serves, when caused to rotate in either direction by the operating knob es, as the actuator to declutch the coil spring 57 from the stud 56 to thereby permit operation of the entrained gears. In this connection, is will be understood that when both the lug 98 of bevel gear 89 and the slotted hub of spur gear are simultaneously in engagement with the coil spring 57, the one exerting the greatest force against the spring 57 will control the action thereof.

For placing the roller unit 17 in working position, the shaft member 23 is first inserted in the associated bushing 33. Then the roller unit 17 is positioned so that its shaft 24, passing first through the opening 48 of the associated retaining member 39, engages the V-shaped entrance 53 of bearing 34, whereupon the operator pushes the roller unit 17 so that its shaft 24 is forced into the opening it wiil be seen that as the shaft 24 moves from the V-shaped entrance 53 into the opening 5 the bearing block 37 is forced to shift away from bearing block as, being guided in such movement by the parallel side walls 41 and 42 of the retaining member 39, and it will also be seen that the aforementioned shifting movement is against the force exerted by coil spring The shaft 24 is retained in the opening 54 for rotation therein by the coaction of bearing blocks 36 and 37, the latter of which bears the weight falling on the shaft 2 5-. it will be understood that the roller unit 18 is placed in working position in a similar manner, but the weight falling on the shaft 29 is taken. by the bearing block 36.

For removing roller unit 17 from its working position,

the operator simply grasps it at the end associated with bearing 34 and pulls it loose from the latter, i. e., pulls with sufficient force to shift shaft 24- from opening 54 outwardly through its flared entrance 53. During such movement of the shaft 2 5 the bearing block 37 is again forced to shift away from its associated bearing block 36 against the force exerted by coil spring 49. Then the opposite end shaft 23 is removed from its bushing 33. It will be understood that the roller unit 18 is removed from working position in a similar manner.

It should be apparent now that an improved clutch arrangement for a system of revoluble members has been incorporated in a vehicle destination sign mechanism, and that the aforementioned arrangement affords an apparatus that functions in a superior manner in that it permits the operator to freely move the curtain to change the destination sign but at the same time effectively prevents movement of the curtain by any other actuating agent, such as action of the spring loaded roller or vibration. In addition, it should be apparent that the clutch is arranged to operate on a single element so that the effect thereon of distortion of the frame of the mechanism is reduced to a minimum. It will be seen also that applicants apparatus is very compact, space being an important factor, and that assembly and manufacturing problems are reduced to a minimum. And, finally, it will be seen that quick-detachable means has been provided for securing the rollers of the apparatus in working position.

Although the apparatus disclosed as embodying the invention has particular utility in the construction of vehicle destination signs certain features are of more general application and, therefore, it is not intended to limit the invention to the exact construction and combination herein shown and described for purposes of illustration as various modifications within the scope of the appended claims may occur to persons skilled in the art.

What is claimed as new and useful is:

1. In a vehicle destination sign mechanism, a rigid supporting frame structure, idler and spring loaded rollers revolubly carried by said frame structure, a curtain on said rollers, a gear train operatively connecting said rollers and manually operable to wind more or less of said ourtain on a selected one of said rollers, said spring loaded roller being operative to draw said curtain taut between said rollers, and clutch means associated with said gear train comprising stationary means on said frame, and a coil spring disposed in embracing relation to said stationary means, said coil spring being revoluble on said stationary means when flexed to expanded condition and frictionally fixed to said stationary means when flexed to contracted condition, said gear train including a pair of closely internested gears on said stationary means disposed in close adjacent relation to said frame structure and in close embracing relation to said coil spring, one of said gears being provided with a protuberance fitted into a way formed in the companion gear, said protuberance and way being arranged for relative movement of said first mentioned and companion gears within limits, the opposite end portions of said spring being disposed in said way respectively on opposite sides of said protuberance, the latter when actuated to drive said companion gear in either direction being operative to expand said spring and to rotate freely, and said companion gear when urged to drive said first gear in either direction being operative to contact said spring and to thereby clutch said stationary means for securement against rotation.

2. In a vehicle destination sign mechanism, a pair of revoluble rollers, a curtain on said rollers, a gear train operatively connecting said rollers and manually operable to wind more or less of said curtain on a selected one of said rollers, and clutch means associated with said gear train comprising stationary means, and a coil spring disposed in embracing relation to said stationary means, said coil spring being revoluble on said stationary means when flexed to expanded condition and frictionally fixed to said stationary means when flexed to contracted condition, said gear train including a pair of closely inter-nested gears on said stationary means disposed in embracing relation to said coil spring, one of said gears being provided with a protuberance fitted into a way formed in the companion gear, said protuberance and way being arranged for relative movement of said first mentioned and companion gears within limits, the opposite end portions of said spring being disposed in said way respectively on opposite sides of said protuberance, the latter when actuated to drive said companion gear in either direction being operative to expand said spring and to rotate freely, and said companion gear when urged to drive said first gear in either direction being operative to contract said spring and to thereby clutch said stationary means for securement against rotation.

3. In a vehicle destination sign mechanism, a pair of revoluble rollers, a curtain on said rollers, a gear train operatively connecting said rollers and operable to Wind more or less of said curtain on a selected roller, and clutch means associated with said gear train comprising stationary means, and a yieldable member on said stationary means, said member being revoluble on said stationary means when flexed to expanded condition and frictionally fixed to said stationary means When flexed to contracted condition, said gear train including a pair of gears on said stationary means disposed side by side and in housing relation to said member, one of said gears being provided with a protuberance fitted into a way formed in the companion gear, said protuberance and way being arranged for relative movement of said first mentioned and companion gears within limits, freely relatively movable portions of said yieldable member being disposed in said way respectively on opposite sides of said protuberance, the latter when actuated to drive said companion gear in either direction being operative to expand said yieldable member and to rotate freely, and said companion gear when urged to drive said first gear in either direction being operative to contract said yieldable member and to thereby clutch said stationary means for securement against rotation.

4. In a vehicle destination sign mechanism, a revoluble roller, a curtain on said roller, mechanism operable to wind more or less of said curtain on said roller, and clutch means associated with said mechanism comprising stationary means, and an expansible member on said stationary means, said member being movable on said stationary means when expanded and frictionally fixed to said stationary means when contracted, said mechanism including a pair of revoluble members on said stationary means one of said revoluble members being provided with an axially extending protuberance presenting toward the companion revoluble member and loosely fitted between freely relatively movable portions of said expansible member, the latter portions being in turn loosely fitted into said companion revoluble member, said expansible and pair of revoluble members being thereby arranged for movement relative to one another within limits, said protuberance bearing revoluble member when actuated to drive said companion revoluble member in either direction being operative to expand said expansible member and to rotate freely, and said companion revoluble member when urged to drive said protuberance bearing revoluble member in either direction being operative to contract said expansible member and to thereby clutch said stationary means for securement against rotation.

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